Name______
Beak of the Finch Activity
On the Galapagos Islands today there are 16 species of closely related finches.
The birds are all about the same size (10–20 cm). The most important differences between species are in the size and shape of their beaks, and the beaks are highly adapted to different food sources. The birds are all brownish or black. Their behavior differs, and they have different song melodies. The current belief by scientists is that one species of finch arrived on the islands and evolved to fill the many niches that were not being filled by other birds. One species evolving to fill many different niches is an example of adaptive radiation.
In August 2006 in the Journal Nature, a group led by Harvard biologist Clif Tabin showed that the beak shapes of Darwin's finches are due to slightly different timing and spatial expressions of a gene called calmodulin. Calmodulin is used by the developing embryo to help lay down skeletal features (including the beak) and using microarray data and early embryo staining from each of the species, this groups could show how the different beak shapes were obtained.
Today you are going to participate in an activity designed to demonstrate how different adaptations help different birds in collecting different types of food.
You will be given a tool used to represent a bird beak and will be asked to collect as much “food” as you can in a 30 second period. Then you will compare what how “birds” with different “beak adaptations” are better at collecting different types of seeds.
Hypothesis: Which tool do you predict will be best fit? WHY?
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My Tool ______
Provide a brief description of your tool. What does it look like?
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Draw a picture of your tool below
What types of food do you think it will be best at collecting? Why do you think this?
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Trial One – All food supplies available
Data table 1 -What I Collected:
______Beans
______Pasta
______Pipe Cleaners
Class data- Trial 1
Average collected by each tool
Trial 2 – All worms have died off
Data table 2 -What I Collected:
______Beans
______Pasta
Class data- Trial 2
Average collected by each tool
Trial Three – Pasta supply on island has been wiped out
Data table 3 - What I Collected:
______Beans
Class data- Trial 3
Average collected by each tool
Analysis questions:
1. Which tool collected the most seeds on average?
2. What type of food was it best at collecting?
3. How do these different tools represent different adaptations?
4. Which type of seed was the bird that collected the least amount of seeds best at collecting?
5. If the environment changed such that the seed type from question #4 was more abundant, what do you think would happen to the population of that bird?
6. Does having a different shape beak or different tool help reduce competition between the birds searching for food? Explain why or why not.